1. Field of the Invention
The present invention relates to a method for controlling equipment in a semiconductor manufacturing system, and more particularly, to a method for automatically controlling preventative maintenance (PM) cycles through a PM controlling module.
2. Description of the Related Art
Generally, the fabrication of semiconductor devices involves highly precise processes that require finely tuned precision equipment. Several pieces of precision equipment are typically employed in sequence and arranged on a semiconductor processing line. The operation of each piece of precision equipment on the line is closely monitored by operators to maintain and enhance the efficiency of the processing line.
As shown in FIG. 1, conventional fabrication equipment 3 are disposed on a conventional processing line. When a lot (not shown) of workpieces, such as wafers, are introduced into the equipment 3, the equipment 3 performs a fabrication process on the lot. The equipment 3 is connected on-line to a host computer 1 through an equipment server 4. An operator interface (O/I) 2, for example an operator interface personal computer (O/I PC), is also connected on-line to the host computer 1. Through the O/I 2, an operator informs the host computer 1 that a process using the equipment 3 is about to commence. The operator inputs basic manufacture data, e.g., the identification number (ID) of the lot to be processed in the equipment 3 and the ID of the equipment 3 for performing the process with the lot, into the host computer 1.
Then, based on the input basic manufacture data, the host computer 1 searches its data base for the process condition data to be applied to the process on the lot. The host computer 1 immediately downloads these process condition data, including preset process settings, to the equipment. Process settings may include, for example, a desired process time duration or a desired process temperature.
Thereafter, the operator checks the process condition data and inputs a process commencing command or a process terminating command. The lot is then automatically and rapidly routed into and out of the equipment 3. In this manner, the process equipment 3 performs on the workpieces of each lot based on the process settings received.
While the processes are being performed, various operational parameters, e.g., the amount of time the equipment 3 has been operating and the number of the wafers that have been processed in the equipment 3, are continuously monitored by the operator. In the event that certain operational parameters exceed predetermined levels that define periodic preventative maintenance cycles, the operator performs preventative maintenance on the equipment 3 to prevent, in advance, damage to the equipment.
However, such a conventional controlling system suffers from several problems. First, since detecting the preventative maintenance cycle event is determined by the subjective actions of an operator, the actual cycle may vary among operators, which results in lack of consistency in performing the preventative maintenance. Secondly, when an error occurs in detecting the preventative maintenance cycle event, the equipment may be damaged. Thirdly, in order to detect the preventative maintenance cycle event, the operator is required to be at the manufacturing line to continuously monitor the respective equipment at their own consoles, which results in reduced efficiency.